1. Field of the Invention
The present invention relates to a liquid ejection head, an image forming apparatus and a method of manufacturing a liquid ejection head, and more particularly, to a liquid ejection head has a laminated structure constructed from a plurality of plates bonded together, an image forming apparatus comprising the liquid ejection head, and a method of manufacturing the liquid ejection head.
2. Description of the Related Art
An image forming apparatus is known which forms images on a recording medium, such as paper, by ejecting ink from nozzles toward the recording medium, while moving a liquid ejection head having an arrangement of a plurality of nozzles and the recording medium, relatively with respect to each other.
A known liquid ejection head mounted in an image forming apparatus of this kind is, for example, a piezo type liquid ejection head, in which ink is supplied to pressure chambers connected to nozzles, and the volume of the pressure chambers is changed, thereby causing the ink inside the pressure chambers to be ejected from the nozzles, by applying a drive signal corresponding to the image data to piezoelectric elements which are installed through a diaphragm plate on the outer side of the pressure chambers.
On the other hand, there are also known thermal jet liquid ejection heads which generate a bubble by heating the ink by means of a heater, or other heating element, and eject an ink droplet by means of the pressure thus generated.
Methods for manufacturing a liquid ejection head are known in which a liquid ejection head is constructed by bonding a plurality of plates together. Furthermore, when manufacturing a liquid ejection head, it is necessary to provide electrodes and electrical wires for supplying electrical signals to the actuators which form pressure generating devices, such as piezoelectric elements.
Japanese Patent Application Publication No. 9-277521 (and in particular, FIG. 1) discloses a case where a flow channel substrate formed with ink flow channels and a diaphragm formed with piezoelectric elements are bonded together by a sheet adhesive, whereupon the diaphragm and piezoelectric elements are bonded together by solder.
Japanese Patent Application Publication No. 2003-211677 (and in particular, FIG. 2) discloses a case where a base plate formed with ink channel grooves is bonded by adhesive to a heater board formed with heaters, and the heater board is then bonded to a heater drive IC by using an anisotropic conductive film (ACF), or the like.
However, if the bonding between the lamination plates and the electrical bonding for supplying electrical signals to the actuators are carried out by separate steps, then the processing is time-consuming and it is difficult to restrict manufacturing costs.
Furthermore, there are demands for improved image quality, and in order to respond to these demands, it has been necessary to arrange nozzles in a two-dimensional array, as well as increasing the nozzle density. In order to achieve both two-dimensional arrangement and high-density arrangement of the nozzles in this way, there have been the issues of how to dispose the electrical wiring, and how to actually carry out the bonding between the lamination plates, and the electrical bonding for supplying an electrical signal to the actuators.